The present invention relates generally to solar heating systems, and more particularly to a combination solar heating system for supplementing building heat and preheating a supply of domestic hot water.
With the advent of higher utility prices, the use of solar energy systems has become more attractive. In general, solar energy systems can be classified in two groups, i.e., active and passive systems.
Active solar energy systems are capable of supplying a large portion of the energy required to operate a building, and thereby substantially reduce utility costs. Additionally, active systems can be easily retrofitted on existing buildings, normally without the need for major structural changes. However, the initial capital cost involved with installing an active solar energy system is normally very substantial. The capital expense of active solar energy systems results, in part, from use of expensive, high temperature collectors. Also, greater heat transfer occurs across large temperature differentials, such as those produced in active solar collectors. Consequently, not only are conventional active high temperature solar energy systems more expensive, they are generally less efficient due to the high heat transfer resulting from high temperature differentials. Similarly, maintenance and upkeep costs of active solar systems can be very high depending upon the system utilized. Therefore, although active systems are capable of providing a large portion of the energy needs of a building, active systems are less efficient and the cost involved with initial capital expenditures and maintenance and upkeep result in a long payback period.
Passive systems, on the other hand, require less capital expense to implement and less maintenance and upkeep than active solar energy systems and are generally more efficient due to the low temperature heat collected. However, passive systems normally cannot be easily retrofitted to existing buildings without major structural changes resulting in large capital expenditures. Additionally, passive systems normally supply a small percentage of the energy needs of a building in comparison to active systems and require large, bulky and awkward heat storage devices. Consequently, passive systems normally do not reduce utility costs in the same manner as active solar energy systems, and similarly result in a long payback period.
Therefore, it would be advantageous to provide a system which could be retrofitted to existing buildings to supply a large percentage of the energy requirements of the building without the need for large, bulky and awkward passive storage devices, as well as a system which is highly efficient in operation, requires low maintenance and upkeep, and low initial capital expense.